1. Field of Invention
The present invention pertains to pump and injection valve systems for use with liquid chromatography. More particularly, the present invention pertains to a combined pump/injection valve for injection of a nanoliter-sized sample into a chromatography column utilizing an single piece as the barrel of the pump and as the stator of the valve, thus eliminating any need for connections between the pump and valve.
2. Description of the Related Art
High performance liquid chromatography (HPLC) is generally performed using pumps, columns and injection valves scaled to deliver fluids at flow rates measured in cubic centimeters of fluid per minute. These components are typically separate and joined together to provide a system for HPLC. Unfortunately, these systems require relatively large sample volumes, large mobile phases, and large flow rates for analysis.
Additionally, these relatively large systems frustrate generate of field portable HPLC units, where there is a need for a lightweight robust flow system which uses a minimum of mobile phase during an analysis.
It would therefore be desirable to provide an integrated nano-scale pump and injection valve for high performance liquid chromatography.